A guide to water testing in developing countries using a Portable Microbiology Laboratory, and how to pasteurize contaminated water using sunshine and a simple solar cooker.
Album by Bob Metcalf. Photos by Bob Metcalf. 1 - 127 of 127 Total. 1502 Visits.
1 Water - Safe to Drink? Nepal
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6 Mwamongu Village water source, Tanzania
7 Water source in Dar es Salaam, Tanzania
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9 The presence of the bacterium Escherichia coli indicates recent fecal contamination of water.
10 Water tests should provide this information
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14 Components of the Portable Microbiology Laboratory with Colilert and Petrifilm tests for E. coli
15 Old, inexact methods on the left, to be replaced by modern tests for E. coli, right
16 Portable Microbiology Laboratory. Materials for 25 water tests in gallon-sized plastic bag
17 Prof. Metcalf holds the two Portable Microbiology Laboratory tests: Colilert MPN tube, and E. coli count Petrifilm.
18 Colilert: A presence/absence test for E. coli in bottles or tubes
19 Colilert for 100 ml, left, and 10 ml, tubes on right.
20 Colilert is an approved water testing method in 40 countries
21 ONPG and MUG are the two substates for E. coli in Colilert
22 How to use Colilert MPN. Collect water in sterile WhirlPak (open well in Temeke Municipality, Dar es Salaam, Tanzania)
23 Carefully remove cap from Colilert tube
24 Use sterile pipette to add 10 ml of water source
25 Carefully replace cap
26 Shake tube to dissolve chemicals
27 Incubate tubes at 35°C for next day results
28 Tubes can also be incubated next to one's body to obtain next day results.
29 Body incubation of Colilert tubes
30 Next day Rresults Clear = no coliform bacteria. Yellow (ONPG+) = coliform bacteria present, possibly E. coli
31 Use a battery-operated long UV light to shine on tubes. Blue fluorescence = MUG +, E. coli is present, water not safe to drink.
32 The best test for E. coli in foods: E. coli Count Petrifilm
33 Two substrates in Petrifilm for E. coli, lactose and BCIG
34 To use Petrifilm, label sample source and time
35 Use sterile pipette to collect exactly 1 ml of water
36 Raise the edge of film to expose nutrient circle
37 Add 1 ml of water sample to nutrient circle
38 Carefully roll down film onto nutrient circle
39 Use flat side of plastic spreader to gently distribute 1 ml over entire circle
40 Petrifilms ready for incubation
41 Petriflms covered with firm cardboard enables incubation on one's body, ~20 doublings for invisible bacteria to develop into visible colonies
42 Results usually in 10-18 hr. E. coli = blue colonies with gas. Coliforms besides E. coli = red with gas.
43 Petrifilm & Colilert tests correlate with risk of disease, WHO Guidelines for Drinking Water Quality, 2nd Edition.
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45 UN Habitat Water Testing Booklet, November, 2010
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48 Ready to start workshop. Boniphace translates for Prof. Metcalf
49 Two water sources in Saka Saka. From a pump (green bucket) and an open stream (yellow bucket).
50 Adults will sample either pump or stream water
51 Mixing inoculated Colilert tubes, to incubate overnight
52 Petrifilms also inoculated by either pump or stream water
53 Next day demonstration of solar cooking, solar water pasteurization
54 Next day results: Pump water yellow, MUG -, no E. coli. Stream yellow and MUG+, E. coli present.
55 Examining Petrifilms the next morning
56 Next day Petrifilm results are clear.
57 Stream water (front) with ~100 E. coli colonies on each Petrifilm, very high disease risk. Pump water with coliform bacteria, but not E. coli, low disease risk.
58 All villagers see results of grossly contaminated stream water, no E. coli contamination of pump water.
59 Solar cooked rice in 2 hr
60 Providing a year's supply of water testing materials to Saka Saka health workers
61 Solar water pasteurization and cooking demonstrated in Saka Saka. This could be replicated in villages worldwide.
62 Water testing/solar pasteurization workshop for Village Chiefs and Village Health workers, Meatu District, Tanzania, 2001
63 Village health workers examine results the following day
64 Village chief knows that MUG+ Colilert means that E. coli was in the town's river water source, unsafe water
65 Health worker finds >10 E. coli on Petrifilm, town river source poses a very high risk of disease
66 Boniphace explaining Petrifilm results of village water sources Meatu
67 Workshop participants given Colilert tubes to test home water sources, Nyakach, Kenya, 2003
68 Colilert tubes incubated overnight in Nyakach
69 All home water sources ONPG +, contain coliform bacteria
70 All water sources from shallow wells also contain E. coli
71 Collecting Nyakach shallow well water for testing
72 Results of Nyakach shallow well - > 10 E. coli/ml very high risk of disease
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75 Students at California State University, Sacramento, who contributed to water pasteurization work
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77 Water Pasteurization article, 1984
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79 Water Pasteurization Indicator (WAPI). When water reaches 65°C (149°F), wax melts and falls to the bottom. Water is pasteurized.
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82 Use a Cookit solar cooker. 5 liters pasteurized in 3 hours of sunshine
83 Article on Cookit and WAPI to pasteurize water, 1999
84 Water vendor collecting river water, Mwanhuzi town, Meatu District, Tanzania, 2000
85 Water vendors try to sell water in Mwanhuzi
86 Guest House (hotel)
87 River water provided for guests
88 After testing river water, collect for solar pasteurization
89 Heating river water in Cookit
90 Temperature >60°C in 2 hours
91 WAPI wax melted, water is pasteurized
92 Ready to test pasteurized water
93 Micro tests before (top) and after solar pasteurization
94 Solar cooking & solar water pasteurization in Nyakach, Kenya
95 Solar cook in Nyakach with WAPI
96 Africa Women and Water Conference, Nairobi, July, 2008
97 Water testing session
98 Inoculating Petrifilms and Colilert tubes with water from their home areas
99 Next day results of Nigeria water
100 Examining Petrifilm results
101 Prof. Metcalf shows 2004 Nobel Peace Prize winner Prof. Wangari Maathai Colilert test results
102 And Petrifilm results
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104 In Bondo, Kenya, With Laban Onongno, UN-Habitat Chief Technical Advisor, Lake Victoria Wat/San Program
105 Prof. Metcalf leads workshop for Bondo community, December, 2008
106 Inoculating Colilert test with 10 ml of Bondo drinking water source
107 Petrifilm test of Bondo drinking water source
108 Next day results in Bondo
109 Now we're microbiologists!
110 Results from nine Bondo water drinking water sources
111 PML methods taught in Bondo by Gobei Secondary School teacher Tobias Amolo, July, 2009
112 Prof. Metcalf presents PML materials to Mr. Amolo, July, 2009
113 Class results of local water sources before and after WaterGuard treatment.
114 Test results before and after chlorination of water source
115 UN-Habitat workshop in Kisumu, Kenya, July, 2010
116 UN-Habitat water testing workshop, Harar, Ethiopia, November, 2010
117 Harar certificate
118 World Water Congress, Montreal, Sept 19-23, 2010
119 IWHA sponsorship of booth at World Water Congress
120 Booth table becomes a laboratory
121 PML to Zimbabwe
122 Poster at World Water Congress
123 World Water Week, Stockholm, Sweden, August 20-26, 2011
124 UN-Habitat booth. Demonstrating water testing.
125 Portable Microbiology Laboratory for World Vision, Ghana
126 Prof. Metcalf and UN Habitat's Lars Stordal at Rwanda workshop location
127 Each workshop participant received a mini-PML, materials for 10 water test, and a WAPI
